Toxicity of the insecticide chlorpyrifos to the South American toad Rhinella arenarum at larval developmental stage

LIENDRO, NATACHA; FERRARI ANA; MARDIROSIAN MARIANA; LASCANO CECILIA INÉS; VENTURINO ANDRÉS

ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam ; Año: 2015 vol. 39 p. 525 - 535

1382-6689

Chlorpyrifos (CPF) is an insecticide widely used for pest control in the fruit-productive region of North Patagonia, Argentina, where it is found in uperficial waters. The aim of this study was to establish the toxic effects of CPF in Rhinella arenarum toad larvae as a potentially exposed species. We determined the 96h-LC50 (1.46 ± 0.27 mg/L), the LOEC (0.81 mg/L, LC10) and NOEC (0.43 mg/L, LC1) for CPF lethality as endpoint. We also analyzed biochemical biomarkers in larvae exposed to sublethal CPF concentrations. The IC50 for cholinesterase was 0.113±0.026 mg/L, one order of magnitude lower than the LC50. Carboxylesterase activity was inhibited, buffering OP toxicity on holinesterase. Reduced gluthatione increased after 24 h as an antioxidant response, and decreased at 96 h together with catalase activity, due to oxidative stress. These biochemical effects suggest a threat posed by environmentally relevant CPF concentrations to R. arenarum larvae progression.